If that's what he said, Robert Harley was wrong. One of the effects of bi-wiring is to change [slightly] the way the crossover behaves. You are essentially adding some resistance, capacitance, and inductance into the circuit that divides the signal between the drivers. The changes you make might be for better or for worse. If the designer of the speaker did a good job, you should use the same wiring system he did when he designed the crossover. If he used single wiring when he designed the crossover, changing from single wire to bi-wiring will only mess up his design. If he used bi-wiring, then you need to find out what wire he used, and in what lengths, so you can simulate the conditions under which he approved the design. Likewise for tri- or quad- wiring.